Nice job on the sketch. I wonder if you ever heard of Darrel Tank 5 Pencil Method. He has a wonderful website, free lessons and great direction in helping not only the sketcher but painter alike. Your sketch is very well done, some more graduations of the edges to ing in a more 3D effect can be achieved by varying the pencil grade. Making it look like a photograph is possiable. You have a eye for details, texture and balance. Maybe next time have the top of her head in view.